Category:Iridescent clouds

Iridescent clouds are composed of very (locally) homogeneous, small droplets. Iridescence occurs most in thin altocumulus or cirrocumulus, often at the beginning of their formation. It is the result of diffraction around droplets, just like in Coronae.

The iridescence pattern is irregular, sometimes following the clouds borders, instead of circular as in corona rings, because the size of droplets slightly varies from one region of cloud to the next.